While rare, there can sometimes be a piece of plastic from manufacturing blocking the brass contacts inside the socket, preventing good contact with the bulbs. It's also possible is that one or both of the brass contacts inside the socket have been bent out of place.
With the set unplugged, using the image below as a reference, check the affected socket to see if it needs any adjustments. A small tool such as a toothpick or tweezers is an ideal tool for the task.
After adjusting, screw your bulb back into the socket and plug it back into power to see if this fixed the problem.
If you're still having issues, please don't hesitate to contact us for additional assistance.
